ACK: [PATCH 1/1][SRU][C] vhost: fix OOB in get_rx_bufs()
Stefan Bader
stefan.bader at canonical.com
Tue Feb 5 10:12:10 UTC 2019
On 04.02.19 21:22, Tyler Hicks wrote:
> From: Jason Wang <jasowang at redhat.com>
>
> After batched used ring updating was introduced in commit e2b3b35eb989
> ("vhost_net: batch used ring update in rx"). We tend to batch heads in
> vq->heads for more than one packet. But the quota passed to
> get_rx_bufs() was not correctly limited, which can result a OOB write
> in vq->heads.
>
> headcount = get_rx_bufs(vq, vq->heads + nvq->done_idx,
> vhost_len, &in, vq_log, &log,
> likely(mergeable) ? UIO_MAXIOV : 1);
>
> UIO_MAXIOV was still used which is wrong since we could have batched
> used in vq->heads, this will cause OOB if the next buffer needs more
> than 960 (1024 (UIO_MAXIOV) - 64 (VHOST_NET_BATCH)) heads after we've
> batched 64 (VHOST_NET_BATCH) heads:
> Acked-by: Stefan Hajnoczi <stefanha at redhat.com>
>
> =============================================================================
> BUG kmalloc-8k (Tainted: G B ): Redzone overwritten
> -----------------------------------------------------------------------------
>
> INFO: 0x00000000fd93b7a2-0x00000000f0713384. First byte 0xa9 instead of 0xcc
> INFO: Allocated in alloc_pd+0x22/0x60 age=3933677 cpu=2 pid=2674
> kmem_cache_alloc_trace+0xbb/0x140
> alloc_pd+0x22/0x60
> gen8_ppgtt_create+0x11d/0x5f0
> i915_ppgtt_create+0x16/0x80
> i915_gem_create_context+0x248/0x390
> i915_gem_context_create_ioctl+0x4b/0xe0
> drm_ioctl_kernel+0xa5/0xf0
> drm_ioctl+0x2ed/0x3a0
> do_vfs_ioctl+0x9f/0x620
> ksys_ioctl+0x6b/0x80
> __x64_sys_ioctl+0x11/0x20
> do_syscall_64+0x43/0xf0
> entry_SYSCALL_64_after_hwframe+0x44/0xa9
> INFO: Slab 0x00000000d13e87af objects=3 used=3 fp=0x (null) flags=0x200000000010201
> INFO: Object 0x0000000003278802 @offset=17064 fp=0x00000000e2e6652b
>
> Fixing this by allocating UIO_MAXIOV + VHOST_NET_BATCH iovs for
> vhost-net. This is done through set the limitation through
> vhost_dev_init(), then set_owner can allocate the number of iov in a
> per device manner.
>
> This fixes CVE-2018-16880.
>
> Fixes: e2b3b35eb989 ("vhost_net: batch used ring update in rx")
> Signed-off-by: Jason Wang <jasowang at redhat.com>
> Signed-off-by: David S. Miller <davem at davemloft.net>
>
> CVE-2018-16880
>
> (backported from commit b46a0bf78ad7b150ef5910da83859f7f5a514ffd)
> [tyhicks: VHOST_NET_BATCH is VHOST_RX_BATCH in Cosmic]
> Signed-off-by: Tyler Hicks <tyhicks at canonical.com>
Acked-by: Stefan Bader <stefan.bader at canonical.com>
> ---
> drivers/vhost/net.c | 3 ++-
> drivers/vhost/scsi.c | 2 +-
> drivers/vhost/vhost.c | 7 ++++---
> drivers/vhost/vhost.h | 4 +++-
> drivers/vhost/vsock.c | 2 +-
> 5 files changed, 11 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
> index 6b86ca8772fb..b72bfeda82a5 100644
> --- a/drivers/vhost/net.c
> +++ b/drivers/vhost/net.c
> @@ -984,7 +984,8 @@ static int vhost_net_open(struct inode *inode, struct file *f)
> n->vqs[i].rx_ring = NULL;
> vhost_net_buf_init(&n->vqs[i].rxq);
> }
> - vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX);
> + vhost_dev_init(dev, vqs, VHOST_NET_VQ_MAX,
> + UIO_MAXIOV + VHOST_RX_BATCH);
>
> vhost_poll_init(n->poll + VHOST_NET_VQ_TX, handle_tx_net, EPOLLOUT, dev);
> vhost_poll_init(n->poll + VHOST_NET_VQ_RX, handle_rx_net, EPOLLIN, dev);
> diff --git a/drivers/vhost/scsi.c b/drivers/vhost/scsi.c
> index fe7914dffd8f..0c3e413fe89f 100644
> --- a/drivers/vhost/scsi.c
> +++ b/drivers/vhost/scsi.c
> @@ -1398,7 +1398,7 @@ static int vhost_scsi_open(struct inode *inode, struct file *f)
> vqs[i] = &vs->vqs[i].vq;
> vs->vqs[i].vq.handle_kick = vhost_scsi_handle_kick;
> }
> - vhost_dev_init(&vs->dev, vqs, VHOST_SCSI_MAX_VQ);
> + vhost_dev_init(&vs->dev, vqs, VHOST_SCSI_MAX_VQ, UIO_MAXIOV);
>
> vhost_scsi_init_inflight(vs, NULL);
>
> diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
> index c4424cbd9943..cd9ff58d6470 100644
> --- a/drivers/vhost/vhost.c
> +++ b/drivers/vhost/vhost.c
> @@ -389,9 +389,9 @@ static long vhost_dev_alloc_iovecs(struct vhost_dev *dev)
> vq->indirect = kmalloc_array(UIO_MAXIOV,
> sizeof(*vq->indirect),
> GFP_KERNEL);
> - vq->log = kmalloc_array(UIO_MAXIOV, sizeof(*vq->log),
> + vq->log = kmalloc_array(dev->iov_limit, sizeof(*vq->log),
> GFP_KERNEL);
> - vq->heads = kmalloc_array(UIO_MAXIOV, sizeof(*vq->heads),
> + vq->heads = kmalloc_array(dev->iov_limit, sizeof(*vq->heads),
> GFP_KERNEL);
> if (!vq->indirect || !vq->log || !vq->heads)
> goto err_nomem;
> @@ -413,7 +413,7 @@ static void vhost_dev_free_iovecs(struct vhost_dev *dev)
> }
>
> void vhost_dev_init(struct vhost_dev *dev,
> - struct vhost_virtqueue **vqs, int nvqs)
> + struct vhost_virtqueue **vqs, int nvqs, int iov_limit)
> {
> struct vhost_virtqueue *vq;
> int i;
> @@ -426,6 +426,7 @@ void vhost_dev_init(struct vhost_dev *dev,
> dev->iotlb = NULL;
> dev->mm = NULL;
> dev->worker = NULL;
> + dev->iov_limit = iov_limit;
> init_llist_head(&dev->work_list);
> init_waitqueue_head(&dev->wait);
> INIT_LIST_HEAD(&dev->read_list);
> diff --git a/drivers/vhost/vhost.h b/drivers/vhost/vhost.h
> index 6c844b90a168..63f88f8e8184 100644
> --- a/drivers/vhost/vhost.h
> +++ b/drivers/vhost/vhost.h
> @@ -166,9 +166,11 @@ struct vhost_dev {
> struct list_head read_list;
> struct list_head pending_list;
> wait_queue_head_t wait;
> + int iov_limit;
> };
>
> -void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs, int nvqs);
> +void vhost_dev_init(struct vhost_dev *, struct vhost_virtqueue **vqs,
> + int nvqs, int iov_limit);
> long vhost_dev_set_owner(struct vhost_dev *dev);
> bool vhost_dev_has_owner(struct vhost_dev *dev);
> long vhost_dev_check_owner(struct vhost_dev *);
> diff --git a/drivers/vhost/vsock.c b/drivers/vhost/vsock.c
> index d27d7e9b2a9e..379d6571ed4c 100644
> --- a/drivers/vhost/vsock.c
> +++ b/drivers/vhost/vsock.c
> @@ -531,7 +531,7 @@ static int vhost_vsock_dev_open(struct inode *inode, struct file *file)
> vsock->vqs[VSOCK_VQ_TX].handle_kick = vhost_vsock_handle_tx_kick;
> vsock->vqs[VSOCK_VQ_RX].handle_kick = vhost_vsock_handle_rx_kick;
>
> - vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs));
> + vhost_dev_init(&vsock->dev, vqs, ARRAY_SIZE(vsock->vqs), UIO_MAXIOV);
>
> file->private_data = vsock;
> spin_lock_init(&vsock->send_pkt_list_lock);
>
-------------- next part --------------
A non-text attachment was scrubbed...
Name: signature.asc
Type: application/pgp-signature
Size: 833 bytes
Desc: OpenPGP digital signature
URL: <https://lists.ubuntu.com/archives/kernel-team/attachments/20190205/bf64e030/attachment-0001.sig>
More information about the kernel-team
mailing list